Technical Field
This disclosure relates to an electronic apparatus including a sensor unit for an indicating object.
Description of the Related Art
Examples have been increasing in which a sensor unit with which input operations can be made by using a pen-type position indicator, a finger, or the like as an indicating object is used as an input device incorporated in an electronic apparatus. The following fact is one cause thereof. Specifically, this kind of sensor unit can be formed by providing transparent conductors over a transparent substrate. Therefore, if the electronic apparatus includes a display screen, the sensor unit can be disposed to overlap with the display screen and a space for the input device is not particularly needed around a displayed image. This can form the electronic apparatus as small-size apparatus.
In the sensor unit, the plural transparent conductors disposed over the transparent substrate are sequentially scanned to search for the transparent conductor from which a signal transmitted from the indicating object or a signal that is originally transmitted from the sensor unit and returns via the indicating object is detected or search for the transparent conductor whose capacitance changes on the basis of indication by the indicating object. The position of the indicating object is thereby detected corresponding to the position of the transparent conductor from which the signal is detected or the change in the capacitance is detected.
In this case, if the number of transparent conductors that should be scanned is large, the scan time becomes long and the speed of detection of the indicating object decreases in the case of always scanning all of these transparent conductors. Therefore, if the indicating object is moved at high speed in the sensor unit, the speed of detection of the indicating object comes to fail in keeping up with the movement speed of the indicating object and the lowering of the following capability, i.e., the state in which the indicating object cannot be detected in such a manner as to follow the movement, occurs. For this reason, for example in drawing software such as Paintbrush, the motion of an indicating object is coarsely expressed when a scan result of the indicating object is displayed.
The following method has been proposed as a related art. Specifically, in this method, when the position of an indicating object is detected in a sensor unit, a local scan (partial scan) of scanning transparent conductors only around the detected position is carried out. The lowering of the following capability with respect to the high-speed movement of the indicating object due to scanning of the whole of the transparent conductors in the sensor unit (hereinafter, this will be referred to as the all-scan (overall scan)) is thereby covered (for example, Japanese Patent Laid-open No. 2002-297302 and Japanese Patent Laid-open No. 2013-168121).
By the way, as indicated in FIG. 21A for example, there has been the following apparatus as portable apparatus 1 such as a mobile phone terminal in recent years. Specifically, in this apparatus, besides a main indication input unit 3 formed of a sensor unit (not indicated) disposed to overlap with a display screen 2, peripheral indication input units 4A and 4B or the like having functions of button keys for example are provided at a peripheral part of the display screen 2.
In this case, when an indicating object detected by the main indication input unit 3 is a pen-type position indicator, the following troublesome operation is necessary if the peripheral indication input units 4A and 4B are formed of mechanical push-button keys. Specifically, after operating the peripheral indication input unit 4A or 4B formed of the push-button key with a finger, a user holds the pen-type position indicator with the same hand and operates the main indication input unit 3 formed of the sensor unit made to overlap with the display screen 2. Alternatively, the user operates the peripheral indication input unit 4A or 4B formed of the push-button key with one hand and holds the pen-type position indicator with the other hand to operate the main indication input unit 3.
Accordingly, in apparatus of a related art, the button keys of the peripheral indication input units 4A and 4B are also formed of a sensor unit of the same indicating object detection system as the main indication input unit 3. In this case, generally, as indicated in FIG. 21B, a sensor unit 5 forming the main indication input unit 3 is formed to be increased in size and have a wide detection region so that the indicating object can be detected also in the regions of the peripheral indication input units 4A and 4B. In addition, a region 2′ (see a dotted line in FIG. 21B) corresponding to the display region 2 is set to detect the indicating object as the region of the main indication input unit 3 and regions 4A′ and 4B′ (see dotted lines in FIG. 21B) corresponding to the peripheral indication input units 4A and 4B are set to detect the indicating object as detection regions of button key operation.
The sensor unit 5 of the example of FIG. 21B is a sensor unit of the electromagnetic induction system and is composed of a loop coil group 5X formed by arranging plural loop coils in a first direction (e.g., X-axis direction) and a loop coil group 5Y formed by arranging plural loop coils in a second direction (Y-axis direction) orthogonal to the first direction.
According to such a configuration, a user can make indication input operation to the peripheral indication input units 4A and 4B and the main indication input unit 3 corresponding to the display screen 2 by holding the portable apparatus with one hand and holding, e.g., a pen-type position indicator with the other hand, which is convenient.
However, if the sensor unit 5 is formed to have a detection region including the main indication input unit 3 and the peripheral indication input units 4A and 4B as above, there is a problem that the sensor unit 5 structurally having a large area is necessary and it becomes difficult to respond to requests for size reduction of the portable apparatus for recent years and narrowing of a so-called frame around the display screen.
Then, it will be available to form the sensor unit having the region of the main indication input unit 3 corresponding to the display screen 2 as the indication input region and the sensor unit having the region of each of the peripheral indication input units 4A and 4B as the indication input region by different sensor units from each other. This can reduce the size of the peripheral indication input units 4A and 4B set to obtain functions of button keys and thus reduce the above-described problems of size increase of the portable apparatus and so forth.
However, if the plural sensor units are provided in this manner, another problem is caused. Specifically, when a position indicator is located at the peripheral indication input unit 4A or 4B, the position indicator is not being detected in the main indication input unit 3. Thus, the sensor unit 5 is in the all-scan state in which all loop coils of the loop coil groups 15X and 15Y are sequentially scanned and is in the state in which the speed of detection of the indicating object is lowered. Therefore, when the position indicator is moved from the position of the peripheral indication input unit 4A or 4B to the main indication input unit 3, if the speed of the movement of the position indicator is high, possibly the indicating object cannot be detected at the circumferential part in the region of the main indication input unit 3 and the track of the indicating object is lost, so that it takes a long time to detect the indicating object in the main indication input unit 3.
Furthermore, also when the position indicator is located, e.g., near the peripheral indication input unit 4A or 4B in the region of the main indication input unit 3, the following problem is caused if the sensor unit always carries out scan operation for detection of the indicating object in the peripheral indication input units 4A and 4B. Specifically, also when a user makes the position indicator touch the peripheral indication input unit 4A or 4B by mistake carelessly, possibly the peripheral indication input unit 4A or 4B detects the position indicator and the portable apparatus carries out operation corresponding to this detection result.
This disclosure intends to provide an electronic apparatus that is configured to be capable of solving the above problems and includes a sensor unit and a position detecting circuit that detects a position indicated by an indicating object in the sensor unit.